1. Technical Field
This application relates to a vascular device and more particularly to a device for closing openings in vessel walls.
2. Background of Related Art
During certain types of vascular surgery, catheters are inserted through an incision in the skin and underlying tissue to access the femoral artery in the patient's leg. The catheter is then inserted through the access opening made in the wall of the femoral artery and guided through the artery to the desired site to perform surgical procedures such as angioplasty or plaque removal. After the surgical procedure is completed and the catheter is removed from the patient, the access hole must be closed. This is quite difficult not only because of the high blood flow from the artery, but also because there are many layers of tissue that must be penetrated to reach the femoral artery.
Several approaches to date have been used to close femoral access holes. In one approach, manual compression by hand over the puncture site is augmented by a sandbag or weight until the blood coagulates. With this approach, it can take up to six hours for the vessel hole to close and for the patient to be able to ambulate. This inefficiency increases the surgical procedure time as well as the overall cost of the procedure since the hospital staff must physically maintain pressure and the patient's discharge is delayed because of the inability to ambulate.
In another approach to close the vessel puncture site, a clamp is attached to the operating table and the patient's leg. The clamp applies pressure to the vessel opening. The patient, however, must still be monitored to ensure the blood is coagulating, requiring additional time of the hospital staff and increasing the cost of the procedure.
To avoid the foregoing disadvantages of manual pressure approaches, suturing devices have been developed. One such suturing device, sold by Abbott, advances needles adjacent the vessel wall opening and pulls suture material outwardly through the wall adjacent the opening. The surgeon then ties a knot in the suture, closing the opening. One difficulty with the procedure involves the number of steps required by the surgeon to deploy the needles, capture the suture, withdraw the suture, and tie the knot and secure the suture. Moreover, the surgeon cannot easily visualize the suture because of the depth of the femoral artery (relative to the skin) and essentially ties the suture knot blindly or blindly slips a pre-tied knot into position. Additionally. the ability to tie the knot varies among surgeons; therefore success and accuracy of the hole closure can be dependent on the skill of the surgeon. Yet another disadvantage of this suturing instrument is that the vessel opening is widened for insertion of the instrument, thus creating a bigger opening to close in the case of failure to deliver the closure system. It is also difficult to pass the needle through calcified vessels.
U.S. Pat. No. 4,744,364 discloses another approach for sealing a vessel puncture in the form of a device having an expandable closure member with a filament for pulling it against the vessel wall. The closure member is held in place by a strip of tape placed on the skin to hold the filament in place. However, the closure device is still subject to movement which can cause leakage through the puncture. Additionally, if the suture becomes loose, the closure member is not retained and can flow downstream in the vessel. Moreover, since the suture extends through the skin, a potential pathway for infection is created. The closure device in U.S. Pat. No. 5,545,178 includes a resorbable collagen foam plug located within the puncture tract. However, since coagulation typically takes up to twenty minutes and blood can leak in between the plug and tissue tract, manual pressure must be applied to the puncture for a period of time, until the collagen plug expands within the tract.
It would therefore be advantageous to provide a device which would more quickly and effectively close openings (punctures) in vessel walls. Such device would advantageously avoid the aforementioned time and expense of applying manual pressure to the opening, simplify the steps required to close the opening, avoid widening of the opening, and more effectively retain the closure device in the vessel.
Commonly assigned co-pending patent application Ser. No. 10/847,141, filed May 17, 2004, discloses effective vascular hole closure devices which have the foregoing advantages. It would be further advantageous to provide a vascular hole closure device which is adjustable to accommodate different tissue thicknesses and applies a more constant clamping/retaining force between the intravascular and extravascular components of the device irrespective of tissue thickness.